> > So there are at least two potential reasons for that:> > > > - The MP table is simply wrong, and WinXP gets the routing information > > from somewhere else (ie most likely ACPI)> > > > - The MP table is right, and only pin0 is connected, and WinXP only uses > > pin0 (ie it puts the card in some state where all irqs are shared > > across all of the four tulip chips).> > > > Maybe somebody can come up with other schenarios.> > > > It would be interesting to hear what "Device Manager" (or whatever it is> > called) unde WinXP claims the interrupts are on this machine... Are they> > all on irq 48 on XP too? Or has XP gotten magic knowledge somewhere> > (ACPI?) and they are on different irq's?> > > > Linus

How about using 'mptable' (Authored by Pete Zaitcev) to view the bus,pin and ioapic layout? It showed all the INTA,B,C,D pins on a troublesome system of mine and helped track down the problem.